Electronic head pressure control

ABSTRACT

A condenser assembly for use in a refrigeration system to reject heat from refrigerant to an environment. The condenser assembly includes first and second condenser modules each having a condenser coil and valve. Each condenser coil includes an inlet port to receive a refrigerant and an outlet port to discharge the refrigerant. The valve is in fluid communication with the corresponding inlet port and regulates flow of the refrigerant through the corresponding condenser coil A sensor in communication with the refrigeration circuit generates a signal indicative of an inlet pressure of the condenser assembly. A controller is programmed to actuate the first valve to regulate the flow of the refrigerant into first condenser coil, and to actuate the second valve independent of the first valve to regulate the flow of the refrigerant into the second condenser coil to control condenser volume based on the signal indicative of the inlet pressure.

BACKGROUND

The present invention relates to a condenser assembly for use in retail store refrigeration systems, and more particularly to a control of the condenser assembly that regulates condenser volume in communication with the refrigeration system.

Typical retail store refrigeration systems often utilize condenser assemblies including condenser coils to dissipate heat from refrigerant passing through the condenser coils. In large-scale retail store refrigeration systems, oftentimes large conventional condenser assemblies are sized to dissipate, or reject, an amount of heat equal to the heat load of the refrigeration system. In other words, the condenser coils are sized to dissipate the amount of heat in the refrigerant that was absorbed or generated in other portions of the refrigeration system.

Typically, the condenser assemblies are positioned outside the retail store, such as on a rooftop, to allow heat transfer between the condenser coil and the outside environment (i.e., to allow the heat in the refrigerant to dissipate into the outside environment). A mechanical draft may be provided by a fan to air-cool the condenser coil.

Existing condenser assemblies often display poor efficiency in dissipating heat from the refrigerant. As a result, these condenser assemblies can be rather large for the amount of heat being dissipated from the refrigerant, requiring additional space for the condenser assemblies. Further, larger condenser assemblies require more refrigerant in the refrigeration system to maintain adequate operation of the refrigeration system. The refrigeration systems using these large condenser coils often require excess refrigerant to be stored in receivers or tanks so that the condenser coils can be flooded in low ambient temperature conditions to provide winter operation of the condenser assembly. The large amount of refrigerant in these systems increases potential effect to the environment if the refrigerant were released to the atmosphere.

Winter operation requires a smaller condenser assembly capacity to reject heat to the environment as a result of a decrease in ambient temperature. A decrease in ambient temperature results in a condenser capacity increase in the condenser. Some refrigeration systems flood the condenser coils to maintain the refrigeration capacity in the refrigeration system at operational levels under low ambient conditions. These refrigeration systems use mechanical hold-back valves to regulate the refrigerant and to flood portions of the condenser assembly. These valves are configured to maintain the head pressure of the system at an operating pressure sufficient for adequate expansion valve operation. In low ambient temperature conditions, the mechanical hold-back valves force more refrigerant into the condenser (i.e., flooding) to reduce the heat transfer effectiveness of the condenser. The excess refrigerant is distributed from a receiver into the condenser coil to reduce the condenser capacity. In high ambient temperature conditions, the mechanical hold-back valves open to reduce flooding of the condenser and to improve the heat transfer effectiveness of the condenser.

Some other refrigeration systems isolate fifty percent of the condenser assembly (e.g., isolation of one condenser slab in a two-condenser slab assembly) from refrigerant flow due to low ambient conditions. These condenser slabs extend longitudinally along the condenser assembly, and can further utilize flooding to reduce the capacity of the remaining active portion of the condenser assembly. The isolation of one-half of the condenser capacity reduces the effectiveness of the condenser assembly to cool compressed refrigerant. However, these condenser assemblies operate either at full capacity (i.e., zero-percent reduction) or at half capacity (i.e., fifty-percent reduction). These condenser assemblies cannot be isolated to less than fifty percent or more than fifty percent capacity without: at least partial flooding of the condenser assembly to accommodate winter operation.

Typical condenser assemblies include fans that cycle “on” and “off” to maintain adequate control of the condenser capacity under low ambient conditions. For example, when first and second longitudinal condenser slabs of a two-slab assembly are operational, the two fans farthest from the inlet to the condenser (i.e., one fan per slab) cycle “off” to provide a first reduction in condenser capacity. The process continues to cycle two fans “off” until most, if not all fans in the condenser assembly are cycled “off.” After all the fans are cycled “off,” one of the two condenser slabs is isolated. The remaining condenser slab remains active to cool the refrigerant in the refrigeration system. The condenser capacity of the remaining condenser slab is further reduced by flooding a portion of the remaining active condenser slab.

SUMMARY

In one embodiment, the invention provides a condenser assembly to condense a refrigerant for use in a refrigeration system having a refrigeration circuit, and to reject heat of the refrigerant to ambient air of the environment. The condenser assembly includes first and second condenser modules each having a condenser coil and valve. Each condenser coil includes an inlet port to receive a refrigerant and an outlet port to discharge the refrigerant. The valve is in fluid communication with the corresponding inlet port and regulates flow of the refrigerant through the corresponding condenser coil. A sensor in communication with the refrigeration circuit generates a signal indicative of an inlet pressure of the condenser assembly. A controller is programmed to actuate the first valve to regulate the flow of the refrigerant into first condenser coil, and to actuate the second valve independent of the first valve to regulate the flow of the refrigerant into the second condenser coil to control condenser volume based on the signal indicative of the inlet pressure.

In another embodiment, the invention provides a method of regulating a condenser assembly for a refrigeration system that includes a refrigeration circuit having at refrigerant. The method includes providing a first condenser module having a first inlet port and a first outlet port in the refrigeration circuit, and a first valve in fluid communication with the first inlet port. The method also includes providing a second condenser module having a second inlet port and a second outlet port in the refrigeration circuit, and a second valve in fluid communication with the second inlet port. The method further includes generating a signal indicative of a condenser inlet pressure, regulating flow of refrigerant into the first condenser coil, regulating flow of refrigerant into the second condenser coil by actuating the second valve independent of the first valve and varying a volume of the condenser assembly based on the signal indicative of the condenser inlet pressure.

In yet another embodiment, the invention provides a condenser assembly for a refrigeration system having a refrigerant circuit that circulates a refrigerant. The condenser assembly includes a plurality of condenser modules. Each condenser module includes a condenser coil having an inlet port to receive the refrigerant and an outlet port to discharge the refrigerant, and a valve in fluid communication with the first inlet port that actuates to regulate flow of the refrigerant through the condenser coil. The condenser assembly further includes a controller programmed to actuate the valves of the plurality of condenser modules to fluidly connect the condenser coils of the plurality of condenser modules to the refrigeration circuit to define a first condenser volume. The controller is further programmed to selectively actuate at least one valve of the plurality of condenser modules independent of at least two other valves of the remaining plurality of condenser modules to isolate the corresponding at least one condenser coil from the refrigeration circuit to define a second condenser volume that is different from the first condenser volume.

In yet another embodiment the invention provides a method of regulating a condenser assembly for a refrigeration system including a refrigeration circuit that circulates a refrigerant. The method includes providing a plurality of condenser modules, each module including a condenser coil having an inlet port to receive the refrigerant and an outlet port to discharge the refrigerant, and a valve in fluid communication with the first inlet port. The method further includes actuating the plurality of valves and fluidly connecting the condenser coils of the plurality of condenser modules to the refrigeration circuit and defining a first condenser volume based on connecting the condenser coils of the plurality of condenser modules to the refrigeration circuit. The method further includes selectively actuating at least one valve of the plurality of condenser modules independent of at least two other valves of the remaining plurality of condenser modules, isolating the corresponding at least one condenser coil from the refrigeration circuit, and defining a second condenser volume different from the first condenser volume with the at least one condenser coil isolated.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a condenser assembly including four condenser modules.

FIG. 2 is a perspective view of the condenser modules of FIG. 1;

FIG. 3 is a perspective view of the condenser module of FIG. 2, with portions removed to illustrate microchannel condenser coils;

FIG. 4 is a cut-away view of one of the microchannel condenser coils of FIG. 3, exposing multiple microchannels; and

FIG. 5 is a broken view of the microchannel condenser coil of FIG. 3.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

FIG. 1 shows a condenser assembly 10 that may be used in a large-scale retail store refrigeration system (not shown), such as that found in many large grocery stores or supermarkets. In such a refrigeration system, the condenser assembly 10 may be positioned outside the retail store, such as on the rooftop of the store, as part of a refrigeration circuit defined by the refrigeration system to allow heat transfer from the condenser assembly to the outside environment. The role of the condenser assembly 10 in the refrigeration system is to receive compressed, gaseous refrigerant from one or more compressors (not shown), condense the gaseous refrigerant back into its liquid form, and discharge the liquid refrigerant to one or more evaporators (not shown) located inside the store. The liquid refrigerant is evaporated when it is passed through the evaporators, and the gaseous refrigerant is drawn into the one or more compressors for re-processing into the refrigeration system.

The condenser assembly 10 includes an inlet line or inlet header 15, an outlet line or outlet header 20, and a plurality of condenser modules 25. The inlet header 15 is coupled to the plurality of condenser modules 25 to receive refrigerant from the one or more compressors and to distribute the compressed, gaseous refrigerant to the plurality of condenser modules 25. In the illustrated embodiment, an inlet 26 is disposed adjacent an end of the condenser assembly 10. Refrigerant from the one or more compressors is delivered to the inlet header 15 through the inlet 26 at the end of the condenser assembly 10 in the direction of arrow 27. In other embodiments, the inlet 26 may be disposed in other locations, such as adjacent a middle of the condenser assembly 10 where the refrigerant from the compressors may be delivered to the inlet header 15 at a location between an approximately equal number of condenser modules 25.

The outlet header 20 is coupled to the plurality of condenser modules 25 adjacent a bottom of the condenser assembly 10 to receive the cooled, liquid refrigerant from the plurality of condenser modules 25 and to send the refrigerant to the one or more evaporators. In some embodiments, the outlet header 20 may include space to store liquid refrigerant condensed by the condenser assembly 10 to eliminate a separate, dedicated receiver tank in the refrigeration system.

An outlet 28 is disposed adjacent an end of the condenser assembly 10. Refrigerant from the condenser modules 25 is delivered from the outlet header 20 through the outlet 28 to the one or more evaporators from the end of the condenser assembly 10 in the direction of arrow 29. In other embodiments, the outlet 28 may be disposed in other locations, such as adjacent a middle of the condenser assembly 10 where the refrigerant from the condenser modules 25 may be delivered from the outlet header 20 at a location between an approximately equal number of condenser modules 25.

The plurality of condenser modules 25 are supported by a frame 30. The frame 30 provides support to the plurality of condenser modules 25 to adequately support the condenser assembly 10 on a surface (not shown). The frame 30 may be a freestanding structure as shown in FIG. 1. However, the frame 30 may comprise any number of different designs other than that shown in FIG. 1. As such, the illustrated frame 30 of FIG. 1 is intended for illustrative purposes only.

FIG. 1 illustrates the condenser assembly 10 including four condenser modules 25. The condenser modules 25 are arranged such that each module 25 is in parallel with the other modules 25. In addition, each module 25 extends along a lateral direction of the condenser assembly 10 rather than along a longitudinal direction. One of the condenser modules 25 is located adjacent the inlet 26, such that the one condenser module 25 is closer to the inlet than the remaining condenser modules 25. Other embodiments may include less than four or more than four condenser modules 25. If a relatively large heat load must be satisfied, a relatively large condenser assembly 10 having a plurality of condenser modules may be used. However, if a relatively small heat load must be dissipated a relatively small condenser assembly 10 having only one or two condenser modules may be required.

As shown in FIG. 1, each condenser module 25 includes two condenser coils 35, an air moving device 40 having two fans 100, 105, an inlet line or distributor 45, and an outlet regulator or valve 55. In the illustrated embodiment of the condenser assembly 10, each condenser module 25 further includes an inlet regulator or valve 50, with the exception of the condenser module 25 closest to the inlet to the condenser assembly 10. In other embodiments, the inlet valve 50 may be included on each condenser module 25 in the condenser assembly 10.

FIGS. 2 and 3 show one of the plurality of condenser modules 25. Although the illustrated condenser module 25 includes two condenser coils 35, other embodiments of the condenser module 25 may include one condenser coil 35 or more than two condenser coils 35 connected in parallel or in series. Each condenser coil 35 is inclined with respect to horizontal such that the footprint of the condenser module 25 is reduced. The illustrated condenser module 25 shown includes two microchannel condenser coils 35 as disclosed in U.S. Pat. No. 6,988,538 (assigned to Hussmann Corporation). In other embodiments, the condenser coil 35 may be a fin-and-tube condenser coil inclined with respect to horizontal. Still other embodiments may include a condenser coil that is substantially horizontal.

Each condenser coil 35 includes a first inlet port 60, a second inlet port 65, an outlet port 70, an inlet manifold 75, a receiver manifold 80, and an outlet manifold 85. The first inlet port 60 is coupled to the condenser coil 35 adjacent an upper end of the inlet manifold 75 to receive a portion of the refrigerant from the inlet header 15 through the inlet distributor 45. The second inlet port 65 is coupled to the condenser coil 35 below the first inlet port 60 adjacent a lower portion of the inlet manifold 75 to also receive refrigerant from the inlet distributor 45. The outlet port 70 is coupled to the condenser coil 35 at a lower end of the outlet manifold 85 to discharge the refrigerant from the condenser coil 35 into the outlet header 20.

The inlet manifold 75, the receiver manifold 80, and the outlet manifold 85 are fluidly connected by a plurality of microchannels 90 (see FIG. 4). The inlet manifold 75 is coupled to the first and second inlet ports 60, 65 and to the plurality of microchannels 90 adjacent the inlet distributor 45 to distribute refrigerant through the micronchannels 90. The receiver manifold 80 is coupled to a side of the condenser coil 35 that is opposite the inlet and outlet manifolds 75, 85 to receive refrigerant from the inlet manifold 75 through a portion of the plurality of microchannels 90 and to distribute the refrigerant through the remaining of the plurality of the microchannels 90 to the outlet manifold 85. The outlet manifold 85 is coupled to the condenser coil 35 between the outlet port 70 and the remaining of the plurality of the microchannels to receive cooled refrigerant and to distribute the refrigerant to the outlet port 70. A barrier or baffle 95 is disposed between the inlet manifold 75 and the outlet manifold 85 to inhibit flow of refrigerant from the inlet manifold 75 directly to the outlet manifold 85.

The air moving device 40 is attached to an upper portion of the condenser module 25 to draw ambient air over the condenser coil 35. The illustrated embodiment in FIGS. 1-3 shows the air moving device 40 including a first fan 100 and a second fan 105 (e.g., single-speed fans, variable speed fans, etc.). The fans 100, 105 are in fluid communication with separate plenums which are divided by a baffle 110 (FIG. 3). The first and second fans 100, 105 are attached to the condenser module 25 and each are supported in a fan shroud 115 to guide airflow over the microchannels 90. An electric motor (not shown) is supported by the condenser module 25 to drive at least one of the first and second fans 100, 105 using either an AC or DC power source. Some embodiments of the condenser module 25 may include more or less than two fans to generate airflow over the condenser coil 35.

The inlet distributor 45 attaches to the condenser module 25 downstream of the inlet header 15 and upstream of the first and second inlet ports 60, 65 to distribute refrigerant from the inlet header 15 to the first and second inlet ports 60, 65. On condenser modules 25 that include the inlet valve 50, the inlet valve 50 is in fluid communication with the first and second inlet ports 60, 65 and attached to the condenser module 25 adjacent the inlet distributor 45. The inlet valve 50 includes an open position and a closed position to regulate flow of refrigerant into the respective condenser module 25. In the illustrated embodiment, the inlet valve 50 is a solenoid valve, although other valves having open and closed positions are also considered.

The outlet valve 55 is disposed on the condenser module 25 adjacent the outlet port 70 to regulate flow of refrigerant between the condenser coil 35 and the outlet header 20. The outlet valve 55 is a check valve that allows refrigerant to flow from the condenser coil 35 to the outlet header 20 and inhibits flow of refrigerant from the outlet header 20 to the condenser coil 35.

The condenser assembly 10 further includes a sensor 120 and a controller 125. FIG. 1 shows the sensor 120 in electrical communication with the controller 125 and attached to the inlet header 15 adjacent the inlet of the condenser assembly 10. The sensor 120 includes a pressure transducer or other similar device to monitor a condenser inlet pressure. In other embodiments, a sensor may be disposed adjacent an outlet of the condenser assembly 10 to measure a condenser outlet pressure. Still other embodiments may include a sensor disposed in other portions of the refrigeration circuit to measure a corresponding pressure. Yet other embodiments can use sensors that measure the temperature of the refrigerant in the refrigeration system or that measure the temperature of the air surrounding or interacting with the condenser coils, the evaporator coils, or other refrigeration components.

FIG. 1 shows the controller 125 in electrical communication with the first and second fans 100, 105, and the inlet valve 50 of one condenser module 25. The controller 125 is also in electrical communication with the first and second fans 100, 105, and the inlet valves 50 of the remaining condenser modules 25, but is not shown in FIG. 1 for clarity. The controller 125 is coupled to the electric motor to selectively operate the first and second tans 100, 105 to controllably draw air over the condenser coils 35 in response to the condenser inlet pressure. In other embodiments, the first and second fans 100, 105 can be controlled using other methods (e.g., inverters, electronic commutation, etc.).

The controller 125 is coupled to the inlet valve 50 to vary the inlet valve 50 between the open and closed positions to control flow of refrigerant into the condenser coil 35 in response to the condenser inlet pressure. In some embodiments, the controller 125, or portions thereof, may be in electrical communication with the outlet valve 55, as well as other components of the refrigeration system (e.g., compressors, evaporators, thermal expansion valves, etc.). In other embodiments, the controller 125 can base control on other parameters, such as the temperature of the refrigerant in the refrigeration system and the temperature of the air surrounding or interacting with the condenser coils, the evaporator coils, or other refrigeration components. Still other embodiments may include a controller that controls the valve 50 based on a pressure of the refrigeration system other than the condenser inlet pressure, such as a compressor outlet pressure or a compressor inlet pressure.

During operation of the refrigeration system utilizing the condenser assembly 10 the compressed, gaseous refrigerant is directed into the inlet header 15 and through the condenser modules 25 where the heat transfer between the airflow passing over each condenser coil 35 causes the gaseous refrigerant to at least partially condense. The refrigerant flows from the first and second inlet ports 60, 65 into the inlet manifold 75 and through the portion of the condenser coil 35. The refrigerant collects in the receiver manifold 80 and is distributed through the remaining portion of the condenser coil 35 to further discharge heat from the refrigerant into the atmosphere. The cooled, substantially liquid refrigerant flows through the outlet port 70 into the outlet header 20 from the outlet manifold 85. The first and second fans 100, 105 may be activated by the controller to provide and/or enhance the airflow through the condenser coil 35 and to further enhance refrigerant cooling.

The condenser assembly 10 includes a capacity that is indicative of the ability of the condenser assembly 10 to effectively reject heat from refrigerant in the refrigeration circuit to the atmosphere. The condenser capacity varies based on the overall surface area of the condenser assembly 10 that is available to provide heat transfer between the condenser assembly 10 and the atmosphere, and may be affected by ambient temperatures of a surrounding environment or atmosphere. In high ambient air temperature conditions (i.e., summer operation), the condenser capacity to cool refrigerant is relatively low. The high ambient conditions require a high condenser volume to achieve adequate rejection of heat from refrigerant to the atmosphere. In low ambient air temperature conditions (i.e., winter operation), the condenser capacity is relatively high and must be reduced to maintain the condenser inlet pressure due to an increase in heat transfer effectiveness between the condenser assembly 10 and the relatively cool atmosphere. Reduction in heat transfer surface area by decreasing a volume of the condenser during winter operation maintains an effective and efficient refrigeration system.

Winter operation of the condenser assembly 10 requires less condenser capacity to adequately cool refrigerant due to low ambient temperatures. The low ambient temperatures cause refrigerant pressure at the inlet of the condenser assembly 10 to lower and allow less condenser capacity to adequately cool refrigerant flowing through the assembly 10. Likewise, relatively high ambient temperatures cause refrigerant pressure at the inlet of the condenser assembly to increase and cause a need for a higher condenser capacity.

The condenser capacity is at least partially defined by a condenser volume available to reject heat from refrigerant to the atmosphere. The condenser assembly 10 defines a first condenser volume that is indicative of a first condenser capacity when the all inlet valves are open and the plurality of condenser coils 35 are connected to the refrigeration circuit. The refrigerant flows through all available condenser modules 25 to provide adequate cooling for the refrigerant. When the inlet refrigerant pressure drops below the predetermined level, the controller 125 selectively actuates at least one inlet salve 50 independent of the remaining inlet valves 50 to isolate the corresponding condenser module 25 from the refrigeration circuit and to reduce the condenser capacity a first amount.

The condenser assembly 10 defines a second condenser volume that is indicative of a second condenser capacity that is different from the first condenser volume when at least one condenser module 25 is isolated from the refrigeration circuit. The second condenser volume can be more than fifty percent of the first condenser volume by isolating less than one-half of the available condenser modules 25. Alternatively, the second condenser volume can be less than fifty percent of the first condenser volume by isolating more than one-half of the available condenser modules 25. In the condenser assembly 10 shown in FIG. 1, the controller may isolate up to three of the four condenser modules 25 to reduce the condenser capacity. For example, when three of the four condenser modules 25 are isolated from the refrigeration circuit, the second condenser volume is approximately twenty-five percent of the first condenser volume. Inversely, isolation of three of the four condenser modules 25 results in a seventy-five percent reduction of the first condenser volume.

The controller 125 provides effective refrigeration management for the refrigeration system by regulating the condenser capacity. The controller 125 independently operates and controls each condenser module 25 in the condenser assembly 10 and selectively isolates or connects each condenser module 25 with the refrigeration circuit.

The air moving device 40 generates airflow over the condenser coil 35 to regulate the condenser capacity of the condenser assembly 10. The first and second fans 100, 105 are cycled between “on” and “off” conditions to vary the condenser capacity based on the condenser inlet pressure of the condenser assembly 10. Cycling the first and second fans 100, 105 between “on” and “off” conditions varies the condenser capacity of the condenser assembly 10 by adjusting ambient airflow passing over the condenser coils 35. The first and second fans 100, 105 are cycled “off” in response to a low condenser inlet pressure to reduce the condenser capacity. Similarly, the first and second fans 100, 105 are cycled “on” in response to a high condenser inlet pressure to increase the condenser capacity. At least one of the first and second fans 100, 105 remains “on” when refrigerant flows through the corresponding condenser coil 35 of the condenser module 25 that includes those fans 100, 105. The controller selectively cycles at least one of the first fan 100 and the second fan 105 independent of the other of the first fan 100 and the second fan 105 to vary the condenser capacity. In other embodiments, the controller simultaneously cycles the first and second fans 100, 105 between “on” and “off” conditions to vary the condenser capacity. In still other embodiments, the first and second tans 100, 105 can be cycled or controlled by other methods as described above.

The controller 125 also operates the inlet valve 50 to regulate the condenser capacity. The controller 125 manages the refrigeration system by varying the inlet valve 50 between the open and closed positions to isolate the condenser module 25 from the refrigeration circuit. Isolation of the condenser module 25 closes off the condenser coil 35 from refrigerant flowing through the refrigeration circuit. Each inlet valve 50 is operated by the controller 125 independent of the remaining plurality of inlet valves 50 to isolate the corresponding condenser module 25 from the remaining plurality of condenser modules 25. In the illustrated embodiment, the controller is configured to selectively isolate the condenser modules 25 that include the inlet valves 50 without shutting down the condenser assembly 10. Refrigerant continues to flow through the condenser module 25 that is nearest the inlet 26 (i.e., the condenser module 25 without the inlet valve 50), due to the lack of the inlet valve 50 on that condenser module 25. The condenser module 25 without the inlet valve 50 cannot be isolated until the condenser assembly 10 is completely shutdown. In embodiments that include the inlet valve 50 on each condenser module 25, the controller 125 can move the inlet valve 50 on the condenser module 25 that is nearest the inlet 26 to isolate the condenser assembly 10 so that maintenance can be performed on the condenser assembly 10.

If the pressure of the refrigerant at the inlet to the condenser assembly 10 is below a predetermined level, the controller 125 first cycles “off” at least one of the first and second fans 100, 105 of one of the condenser modules 25 to decrease the condenser capacity. The controller 125 cycles “off” the remaining fans 100, 105 as needed to vary the condenser capacity and to maintain adequate refrigerant pressure at the inlet to the condenser assembly 10.

The controller 125 simultaneously cycles “off” any of the first and second fans 100, 105 that are “on” when the corresponding inlet valve 50 is moved to the closed position. There is no need for the first and second fans 100, 105 to operate when the inlet valve 50 is closed because no refrigerant flows through the condenser coil 35 of the respective isolated condenser module 25. In the illustrated embodiment, the controller 125 moves the inlet valve 50 of the condenser module 25 farthest from the inlet of the condenser assembly 10 to the closed position to further decrease the condenser capacity by reducing the condenser volume in response to the condenser inlet pressure below the predetermined level. The controller 125 continues to reduce condenser capacity by closing each of the remaining inlet valves 50 as needed to isolate the remaining condenser modules 25.

In embodiments that include the inlet 26 and/or outlet 28 of the condenser assembly 10 adjacent the middle of the condenser assembly 10, the sequence of shutdown of the condenser modules 25 begins with the condenser module 25 that is farthest from the condenser module 25 that is the last to be shutdown or isolated prior to shutdown of the condenser assembly 10. In the illustrated embodiment, the condenser module 25 that is the last to be deactivated corresponds to the condenser module 25 that is without the inlet valve 50 adjacent the end of the condenser assembly 10. The sequence of isolation moves from the condenser modules 25 located farthest from the condenser module 25 without the inlet valve 50 toward the condenser module 25 without the inlet valve 50, such that the condenser modules 25 that are closest to the condenser module 25 without the inlet valve 50 are the last to be isolated. In other words, the condenser module 25 that is closest to the inlet 26 and/or outlet 28 of the condenser assembly 10 is the last to be deactivated.

The refrigeration management provided by the controller 125 allows precise control of the condenser volume to maintain an adequate condenser inlet pressure. The sequence of isolation of the condenser modules 25 generally begins with the condenser module 25 farthest from the inlet to the condenser assembly 10. The controller 125 isolates the next-farthest condenser module 25 each time the condenser volume must be reduced. When the condenser volume must increase to compensate for an increased condenser inlet pressure, the sequence is reversed. Specifically, the controller 125 opens the inlet valve 50 of the previously-isolated condenser module 25 that is closest to the inlet of the condenser assembly 10. As the condenser inlet pressure increases and there is a need for more condenser volume, the controller 125 opens the inlet valve 50 of the condenser module 25 that is the next-closest to the inlet of the condenser assembly 10. The process continues until there is adequate condenser volume to reject heat from refrigerant to the surrounding environment.

The amount of refrigerant in the refrigeration circuit remains constant during summer and winter operation and reduces the need for large receivers to store refrigerant. Isolation of the condenser module 25 from the refrigeration circuit by the controller 125 limits flow of refrigerant through a portion of the condenser assembly 10. After isolation of the condenser module 25, the outlet valve 55 allows refrigerant within the condenser coil 35 to drain into the outlet header 20. The outlet valve 55 inhibits flow of refrigerant from the outlet header 20 into the condenser coil 35 and isolates the coil 35 from the refrigeration circuit. Draining the refrigerant from the isolated condenser coil 35 maintains the condenser inlet pressure at the predetermined level without the need for a receiver to store excess refrigerant.

When the sensor 120 indicates an increase in the inlet refrigerant pressure above the predetermined level, the controller 125 actuates the inlet valve 50 of at least one condenser module 25 to allow refrigerant to flow into the corresponding condenser coil 35. The controller 125 connects each isolated condenser module 25 one at a time to the refrigeration circuit. If the condenser capacity remains inadequate to cool the refrigerant and to maintain the inlet pressure at about the predetermined level, one or both of the first and second fans 100, 105 may be activated to draw ambient air over the condenser coil 35 of the respective condenser module 25 to improve the condenser capacity. The controller 125 connects enough of the condenser modules 25 to the refrigeration circuit to maintain the inlet condenser pressure at about the predetermined level.

Thus, the invention provides, among other things, an electronic control to regulate condenser capacity and refrigerant charge of a condenser assembly. Various features and advantages of the invention are set forth in the following claims. 

1. A condenser assembly to condense a refrigerant for use in a refrigeration system and to reject heat of the refrigerant to ambient air of the environment, the refrigeration system including a refrigeration circuit, the condenser assembly comprising: a first condenser module including a first condenser coil having a first inlet port to receive the refrigerant and a first outlet port to discharge the refrigerant, and a first valve in fluid communication with the first inlet port and actuable to regulate flow of the refrigerant through the first condenser coil; a second condenser module including a second condenser coil having a second inlet port to receive the refrigerant and a second outlet port to discharge the refrigerant, and a second valve in fluid communication with the second inlet port and actuable to regulate flow of the refrigerant through the second condenser coil; and a controller programmed to selectively actuate the first valve to regulate the flow of refrigerant into the first condenser coil, and programmed to actuate the second valve independent of the first valve to regulate the flow of refrigerant into the second condenser coil to control condenser volume.
 2. The condenser assembly of claim 1, further including a sensor in communication with the refrigeration circuit and configured to generate a signal indicative of an inlet pressure of the condenser assembly, wherein the controller is programmed to actuate the first valve and the second salve based on the signal indicative of the inlet pressure.
 3. The condenser assembly of claim 1, wherein the first condenser module includes a first air moving device disposed adjacent the first condenser coil to draw ambient air over the first condenser coil to regulate a condenser capacity of the condenser assembly a first amount, and wherein the second condenser module includes a second air moving device disposed adjacent the second condenser coil to draw ambient air over the second condenser coil to regulate the condenser capacity a second amount.
 4. The condenser assembly of claim 3, wherein the controller is programmed to actuate the first valve to selectively isolate the first condenser coil from the refrigeration circuit to reduce the condenser capacity of the condenser assembly when the inlet pressure is below a predetermined level.
 5. The condenser assembly of claim 4, wherein the controller is programmed to actuate the second valve to selectively isolate the second condenser coil separate and independent from isolation of the first condenser coil.
 6. The condenser assembly of claim 3, wherein the first air moving device further includes a first fan and a second fan, and wherein the controller is programmed to selectively operate the first fan independent of the second fan to regulate the condenser capacity of the condenser assembly.
 7. The condenser assembly of claim 6, wherein the first condenser module further includes a baffle disposed between the first fan and the second fan to compartmentalize the first condenser module.
 8. The condenser assembly of claim 4, wherein the first outlet port is configured to allow refrigerant to drain from the first condenser coil in response to isolation of the first condenser coil.
 9. The condenser assembly of claim 3, wherein the controller is programmed to selectively operate the first air moving device, and wherein the controller is programmed to selectively operate the second air moving device independent of the first air moving device to regulate the condenser capacity.
 10. The condenser assembly of claim 9, wherein the controller is programmed to selectively operate the first air moving device independent of the first valve, and wherein the controller is programmed to selectively operate the second air moving device independent of the second valve.
 11. The condenser assembly of claim 1, wherein the first condenser module further includes a first regulator disposed on the first outlet port to regulate flow of the refrigerant from the first condenser coil, and wherein the second condenser module further includes a second regulator disposed on the second outlet port to regulate flow of refrigerant from the second condenser coil.
 12. The condenser assembly of claim 1, wherein the controller is programmed to actuate the first valve to selectively connect the first condenser coil with the refrigeration circuit to increase the condenser volume.
 13. The condenser assembly of claim 12, wherein the controller is programmed to actuate the second valve to selectively connect the second condenser coil separate and independent from connection of the first condenser coil to increase the condenser volume.
 14. A method of regulating a condenser assembly for a refrigeration system including a refrigeration circuit having a refrigerant, the method comprising: providing a first condenser module in the refrigeration circuit, the first condenser module including a first condenser coil having a first inlet port and a first outlet port, and a first valve in fluid communication with the first inlet port; providing a second condenser module in the refrigeration circuit, the second condenser module including a second condenser coil having a second inlet port and a second outlet port, and a second valve in fluid communication with the second inlet port; regulating flow of refrigerant into the first condenser coil by actuating the first valve with a controller, regulating flow of refrigerant into the second condenser coil by actuating the second valve with the controller independent of the first valve; and varying a volume of the condenser assembly.
 15. The method claim 14, further comprising generating a signal indicative of a condenser inlet pressure; and varying a volume of the condenser assembly based on the signal indicative of the condenser inlet pressure.
 16. The method claim 14, further comprising varying a condenser capacity of the condenser assembly by selectively drawing ambient air over the first condenser coil; and varying a condenser capacity of the condenser assembly by selectively drawing ambient air over the second condenser coil independent of drawing ambient air over the first condenser coil.
 17. The condenser assembly of claim 16, wherein drawing ambient air over the first condenser coil further includes selectively operating the first air moving device and selectively operating the second air moving device independent of the first air moving device.
 18. The condenser assembly of claim 17, further comprising selectively operating the first air moving device independent of actuation of the first valve, and selectively operating the second air moving device independent of actuation of the second valve.
 19. The method of claim 16, wherein drawing ambient air over the first condenser coil includes operating a first fan of the first air moving device independent from operating a second fan of the first air moving device to vary the condenser capacity.
 20. The method of claim 14, further comprising reducing the condenser volume by isolating the first condenser coil from the refrigeration circuit.
 21. The method of claim 20, wherein regulating flow of refrigerant into the second condenser coil includes selectively isolating the second condenser coil independent from isolating the first condenser coil.
 22. The condenser assembly of claim 20, wherein isolating the first condenser coil further includes draining refrigerant from the first condenser coil.
 23. The condenser assembly of claim 14, further comprising regulating the flow of refrigerant from the first outlet port; and regulating the flow of the refrigerant from the second outlet port.
 24. The method of claim 14, wherein regulating flow of refrigerant into the first condenser coil includes connecting the first condenser coil with the refrigeration circuit and increasing the condenser volume when the condenser inlet pressure is above a predetermined level.
 25. The method of claim 24, wherein regulating flow of refrigerant into the second condenser coil includes selectively connecting the second condenser coil with the refrigeration circuit and increasing the condenser volume independent from connecting the first condenser coil.
 26. A condenser assembly for a refrigeration system having a refrigerant circuit circulating a refrigerant, the condenser assembly comprising: a plurality of condenser modules, each module including a condenser coil having an inlet port to receive the refrigerant and an outlet port to discharge the refrigerant, a valve in fluid communication with the first inlet port and actuable to regulate flow of the refrigerant through the condenser coil; and a controller programmed to actuate the valves of the plurality of condenser modules to fluidly connect the condenser coils of the plurality of condenser modules to the refrigeration circuit to define a first condenser volume, and wherein the controller is programmed to selectively actuate at least one valve of the plurality of condenser modules independent of at least two other valves of the remaining plurality of condenser modules to isolate the corresponding at least one condenser coil from the refrigeration circuit to define a second condenser volume different from the first condenser volume.
 27. The condenser assembly of claim 26, wherein the second condenser volume is less than 50% of the first condenser volume.
 28. The condenser assembly of claim 26, wherein the second condenser volume is more than 50% of the first condenser volume.
 29. The condenser assembly of claim 26, wherein the controller is programmed to selectively actuate the at least one valve of the plurality of condenser modules to define the second condenser volume as one of three possible incremental condenser volumes.
 30. The condenser assembly of claim 29, wherein the incremental volumes are proportional to the number of condenser modules in the plurality of condenser modules.
 31. The condenser assembly of claim 29, wherein the number of condenser modules equals four and the incremental condenser volumes equal 75%, 50%, and 25% of the first condenser volume.
 32. The condenser assembly of claim 26, wherein the refrigerant is hindered from flowing into the corresponding at least one condenser coil in response to isolation of the at least one condenser coil.
 33. The condenser assembly of claim 26, wherein the outlet port is configured to drain the refrigerant disposed in the at least one condenser coil in response to isolation of the at least one condenser coil.
 34. A method of regulating a condenser assembly for a refrigeration system including a refrigeration capacity and a refrigeration circuit circulating a refrigerant, the method comprising: providing a plurality of condenser modules, each module including a condenser coil having an inlet port to receive the refrigerant and an outlet port to discharge the refrigerant, and a valve in fluid communication with the first inlet port; actuating the plurality of valves and fluidly connecting the condenser coils of the plurality of condenser modules to the refrigeration circuit; defining a first condenser volume based on connecting the condenser coils of the plurality of condenser modules to the refrigeration circuit; selectively actuating at least one valve of the plurality of condenser modules independent of at least two other valves of the remaining plurality of condenser modules; isolating the corresponding at least one condenser coil from the refrigeration circuit, and defining a second condenser volume different from the first condenser volume with the at least one condenser coil isolated.
 35. The method of claim 34, wherein defining a second condenser volume includes defining a second condenser volume that is less than 50% of the first condenser volume.
 36. The method of claim 34, wherein defining a second condenser volume includes defining a second condenser volume that is more than 50% of the first condenser volume.
 37. The method of claim 34, wherein defining a second condenser volume includes defining the second condenser volume as one of three possible incremental condenser volumes.
 38. The method of claim 37, wherein defining the second condenser volume further includes defining incremental volumes that are proportional to the number of condenser modules in the plurality of condenser modules.
 39. The method of claim 37, wherein providing a plurality of condenser modules further includes providing four condenser modules and defining the second condenser volume further includes defining three incremental condenser volumes equaling 75%, 50%, and 25% of the first condenser volume.
 40. The method of claim 34, wherein isolating the corresponding at least one condenser coil includes inhibiting flow of refrigerant into the corresponding at least one condenser coil.
 41. The method of claim 34, wherein isolating the corresponding at least one condenser coil further includes draining the refrigerant from the at least one condenser coil through the outlet port. 